diff -r b3992c21b7f3 -r 623dc2651d26 mercurial/hgweb/webutil.py
--- a/mercurial/hgweb/webutil.py	Wed Apr 04 21:17:10 2018 +0900
+++ b/mercurial/hgweb/webutil.py	Wed Apr 04 21:17:55 2018 +0900
@@ -633,7 +633,7 @@
             l = _getcompblock(leftlines, rightlines, oc)
             yield {'lines': l}
 
-def compare(tmpl, contextnum, leftlines, rightlines):
+def compare(contextnum, leftlines, rightlines):
     args = (contextnum, leftlines, rightlines)
     return templateutil.mappinggenerator(_comparegen, args=args,
                                          name='comparisonblock')